--- zzzz-none-000/linux-2.6.19.2/arch/alpha/mm/fault.c	2007-01-10 19:10:37.000000000 +0000
+++ davinci-8020-5505/linux-2.6.19.2/arch/alpha/mm/fault.c	2007-01-19 14:42:56.000000000 +0000
@@ -24,6 +24,7 @@
 #include <linux/smp_lock.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/binfmts.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -55,6 +56,124 @@
 	__reload_thread(pcb);
 }
 
+#ifdef CONFIG_PAX_PAGEEXEC
+/*
+ * PaX: decide what to do with offenders (regs->pc = fault address)
+ *
+ * returns 1 when task should be killed
+ *         2 when patched PLT trampoline was detected
+ *         3 when unpatched PLT trampoline was detected
+ */
+static int pax_handle_fetch_fault(struct pt_regs *regs)
+{
+
+#ifdef CONFIG_PAX_EMUPLT
+	int err;
+
+	do { /* PaX: patched PLT emulation #1 */
+		unsigned int ldah, ldq, jmp;
+
+		err = get_user(ldah, (unsigned int *)regs->pc);
+		err |= get_user(ldq, (unsigned int *)(regs->pc+4));
+		err |= get_user(jmp, (unsigned int *)(regs->pc+8));
+
+		if (err)
+			break;
+
+		if ((ldah & 0xFFFF0000U) == 0x277B0000U &&
+		    (ldq & 0xFFFF0000U) == 0xA77B0000U &&
+		    jmp == 0x6BFB0000U)
+		{
+			unsigned long r27, addr;
+			unsigned long addrh = (ldah | 0xFFFFFFFFFFFF0000UL) << 16;
+			unsigned long addrl = ldq | 0xFFFFFFFFFFFF0000UL;
+
+			addr = regs->r27 + ((addrh ^ 0x80000000UL) + 0x80000000UL) + ((addrl ^ 0x8000UL) + 0x8000UL);
+			err = get_user(r27, (unsigned long*)addr);
+			if (err)
+				break;
+
+			regs->r27 = r27;
+			regs->pc = r27;
+			return 2;
+		}
+	} while (0);
+
+	do { /* PaX: patched PLT emulation #2 */
+		unsigned int ldah, lda, br;
+
+		err = get_user(ldah, (unsigned int *)regs->pc);
+		err |= get_user(lda, (unsigned int *)(regs->pc+4));
+		err |= get_user(br, (unsigned int *)(regs->pc+8));
+
+		if (err)
+			break;
+
+		if ((ldah & 0xFFFF0000U) == 0x277B0000U &&
+		    (lda & 0xFFFF0000U) == 0xA77B0000U &&
+		    (br & 0xFFE00000U) == 0xC3E00000U)
+		{
+			unsigned long addr = br | 0xFFFFFFFFFFE00000UL;
+			unsigned long addrh = (ldah | 0xFFFFFFFFFFFF0000UL) << 16;
+			unsigned long addrl = lda | 0xFFFFFFFFFFFF0000UL;
+
+			regs->r27 += ((addrh ^ 0x80000000UL) + 0x80000000UL) + ((addrl ^ 0x8000UL) + 0x8000UL);
+			regs->pc += 12 + (((addr ^ 0x00100000UL) + 0x00100000UL) << 2);
+			return 2;
+		}
+	} while (0);
+
+	do { /* PaX: unpatched PLT emulation */
+		unsigned int br;
+
+		err = get_user(br, (unsigned int *)regs->pc);
+
+		if (!err && (br & 0xFFE00000U) == 0xC3800000U) {
+			unsigned int br2, ldq, nop, jmp;
+			unsigned long addr = br | 0xFFFFFFFFFFE00000UL, resolver;
+
+			addr = regs->pc + 4 + (((addr ^ 0x00100000UL) + 0x00100000UL) << 2);
+			err = get_user(br2, (unsigned int *)addr);
+			err |= get_user(ldq, (unsigned int *)(addr+4));
+			err |= get_user(nop, (unsigned int *)(addr+8));
+			err |= get_user(jmp, (unsigned int *)(addr+12));
+			err |= get_user(resolver, (unsigned long *)(addr+16));
+
+			if (err)
+				break;
+
+			if (br2 == 0xC3600000U &&
+			    ldq == 0xA77B000CU &&
+			    nop == 0x47FF041FU &&
+			    jmp == 0x6B7B0000U)
+			{
+				regs->r28 = regs->pc+4;
+				regs->r27 = addr+16;
+				regs->pc = resolver;
+				return 3;
+			}
+		}
+	} while (0);
+#endif
+
+	return 1;
+}
+
+void pax_report_insns(void *pc, void *sp)
+{
+	unsigned long i;
+
+	printk(KERN_ERR "PAX: bytes at PC: ");
+	for (i = 0; i < 5; i++) {
+		unsigned int c;
+		if (get_user(c, (unsigned int*)pc+i))
+			printk("???????? ");
+		else
+			printk("%08x ", c);
+	}
+	printk("\n");
+}
+#endif
 
 /*
  * This routine handles page faults.  It determines the address,
@@ -132,8 +251,29 @@
  good_area:
 	si_code = SEGV_ACCERR;
 	if (cause < 0) {
-		if (!(vma->vm_flags & VM_EXEC))
+		if (!(vma->vm_flags & VM_EXEC)) {
+
+#ifdef CONFIG_PAX_PAGEEXEC
+			if (!(mm->pax_flags & MF_PAX_PAGEEXEC) || address != regs->pc)
+				goto bad_area;
+
+			up_read(&mm->mmap_sem);
+			switch(pax_handle_fetch_fault(regs)) {
+
+#ifdef CONFIG_PAX_EMUPLT
+			case 2:
+			case 3:
+				return;
+#endif
+
+			}
+			pax_report_fault(regs, (void*)regs->pc, (void*)rdusp());
+			do_exit(SIGKILL);
+#else
 			goto bad_area;
+#endif
+
+		}
 	} else if (!cause) {
 		/* Allow reads even for write-only mappings */
 		if (!(vma->vm_flags & (VM_READ | VM_WRITE)))